1. Field of the Invention
The present invention relates to a touch panel inspection device, and more particularly to a touch panel inspection device used for evaluating destruction durability performance of a pressure-sensitive touch panel using a resistance film.
2. Description of the Related Art
Conventionally, a pressure-sensitive touch panel using a resistance film has been widely used as an input device for computers, as shown in JP(A)-10-116147.
As shown in FIG. 3, the pressure-sensitive touch panel includes a film 102, a glass plate 103, and transparent conductive films 104A, 104B disposed on inner surfaces of the film 102 and glass plate 103 respectively. The conductive films 104A, 104B are respectively provided with conductors 105A, 105B, which are located at the four side ends of the film 102 and glass 103 and covered with insulators 106A, 106B. A double-sided adhesive tape 107 is disposed between the insulators 106A, 106B, and spacers 108 are disposed at fixed intervals on the conductive film 104B of the glass plate 103 side. Accordingly, the conductive films 104A, 104B are fixed together through the insulators 106A, 106B and the double-sided adhesive tape 107 while keeping a certain gap. Such a touch panel is disposed in a casing 101 to form a touch panel device.
An electric potential distribution is formed in the conductive film 104A by applying suitable voltage thereon in a direction along a film surface through the conductor 105A, and another electric potential distribution is formed in the conductive film 104B by applying suitable voltage thereon in another direction along a film surface through the conductor 105B. When a dedicated pen (not shown) is put on the surface of the film 102, at such a pen-touched position the film 102 and conductive film 104 are deformed downward and the conductive film 104A becomes in contact with the conductive film 104B to become short-circuited. The pen-touched positions with respect to the above two directions can be determined by detecting the voltage values applied through the conductors 105A, 105B respectively at the short-circuited state.
Thus, when the pen is slid or put on the touch panel, the film 102 is bent by using as a fulcrum a portion of the four side ends of the film 102 and glass 103 where the conductors 105A, 105B, the insulators 106A, 106B and the double-sided adhesive tape 107 are disposed. Then, if a pen sliding position is near the portion of the four side ends of the film 102 and glass 103, the bending of the film 102 becomes sharper to cause damage such as tear of the transparent conductive film 104A in the film 102 side.
Thus, as to an area of the touch panel used for the input and display screen of the touch panel device, which is determined on the basis of a positional relationship between the touch panel and a window frame of the casing which defines the input and display screen when the touch panel is incorporated in the casing, it is necessary to verify nonoccurrence of any destructions such as tear of the transparent conductive film 104A on the film side even when the pen is slid on the film 102 in the area used for the input and display screen.
Therefore, conventionally, pressure has actually been applied on the touch panel to inspect its durability by using a device (X-Y plotter) similar to that shown in FIG. 4, as shown in JP(A)-11-119900. The X-Y plotter of FIG. 4 in the conventional technique includes an arm 112 holding a pen member 111, and a drive unit 113 which drives the arm 112 along the surface of a touch panel 114 (X-Y plane (see FIG. 4)). The pen member 111 is held by the arm 112 so as to be moved in a direction (Z direction) vertical to the surface of the touch panel 114. Accordingly, predetermined pressure can be applied on the touch panel 114 by the pen member 111.
However, the conventional technique has had the following inconveniences. First, because the X-Y plotter cannot greatly move the position of a pen tip up and down, when a touch panel incorporated with a casing to form a touch panel device is inspected, the touch panel device having an excessively large or small thickness may cause a problem of impossibility of carrying out inspection. That is, durability of the touch panel on the pen sliding can be inspected for the touch panel used alone by the X-Y plotter in which the pen tip thereof is replaced by a dedicated pen for the touch panel. However, depending on a thickness of the touch panel device, a problem may occur where the pen tip does not reach an input surface of the touch panel device, or there is not enough distance between the pen tip and the input surface of the touch panel device so that the casing impedes an operation of the X-Y plotter.
Additionally, determination of a sliding position on the touch panel in an incorporated state into the casing by calculation makes it necessary to consider all of dimensional tolerance of the touch panel itself, dimensional tolerance of the device casing, and tolerance in incorporation of the touch panel in the device casing, consequently causing a problem of impossibility of carrying out accurate positioning.